The Toffees would like to add more firepower to the ranks before the transfer window slams shut on Tuesday evening.
However, it is unclear how much cash they can splash, even after selling Anthony Gordon to Newcastle United for £45m.
They are keen on Crystal Palace striker Mateta and the Eagles would be prepared to deal, but he may cost as much as £20m to land.
Other clubs are also keen on the striker, with Celta Vigo and Marseille looking at him.
All three sides would like to take Mateta on loan from Crystal Palace, but the Eagles would only consider a sale as they would want to reinvest the cash on fresh faces of their own.
Palace may have to wait to do that though as it is suggested their top targets are either unavailable or expensive.
Mateta has made 16 appearances for Crystal Palace in the Premier League so far this season, with a return of just one goal, which came against Aston Villa.